The performance of certain tasks by an industrial robot may require the robot's sequential use of a plurality of tools of differing types. For efficient utilization of the robot, the tool changing operations should be performable rapidly and automatically, without manual intervention. In many utilizations it is also highly desirable for the tool changing apparatus to be of a purely "passive" type that is free from relatively expensive and maintenance-requiring switches, motors and similar "active" components. In some utilizations it is also highly desirable for the robot to be able to simultaneously interchange a plurality of tools during each tool changing operation.
Tool changing systems for robots or the like are disclosed in U.S. Pat. Nos. 4,486,928, 4,520,550, 4,512,709, 4,510,684 and 4,543,032; and in IBM Technical Disclosure Bulletin Vol. 24, No. 7A, December 1981, pgs. 3273-3275.